“Toxic cabin air breathed by passengers, pilots and cabin crew is linked to cancer, chronic fatigue and neurological problems, according to new research in a World Health Organisation (WHO) journal.

The Public Health Panorama report into so-called aerotoxic syndrome – the name given to the health effects of exposure to bleed air, used to pressurise aircraft cabins, that has been contaminated with chemicals such as engine oil – found a clear link between both short- and long-term symptoms and illnesses and toxic fume events.

It said that in 2015 more than 3.5 billion passengers and 500,000 pilots and cabin crew were exposed to low levels of engine oils in the air.

At a glance | What is a fume event?

A fume event is when bleed air used to pressurize the cabin of an aircraft is contaminated by chemicals such as engine oil, hydraulic fluid, or other potentially hazardous chemicals.

The CAA says: “Up to half the cabin air is re-circulated and passes through high efficiency filters, similar to those used in hospital operating theatres, to remove bacteria, viruses and other particles before it is mixed with outside air from the air-conditioning units.”

Campaigners say that if a fault occurs in the engine seals, then the air can become contaminated with neurotoxic chemicals such as tricresyl phosphate.

“Aircraft air supplies contaminated by pyrolysed engine oil and other aircraft fluids can reasonably be linked to acute and chronic symptoms, findings and diagnoses, thus establishing causation,” read the report, authored by Susan Michaelis from the University of Stirling, in association with Vyvyan Howard from the University of Ulster and Jonathan Burdon, a consultant respiratory physician from Melbourne.”